<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<style>
/* 第一种定位 */
/* .parent {
    border: 2px solid #333;
    width: 100px;
    height: 100px;
    position: absolute;
}
.test {
    position: absolute;
    left: 29%;
    top: 25%;
    width: 40px;
    height: 40px;
    background-color: pink;
} */


/* 第二种弹性盒子 */
/* .parent {
    border: 2px solid #333;
    width: 100px;
    height: 100px;
    display: flex;
    justify-content: center;
    align-items: center;
}
.test {
    width: 40px;
    height: 40px;
    background-color: pink;
} */


/* 第三种是盒子内外边距 */
.parent {
    border: 2px solid #333;
    width: 100px;
    height: 100px;

}
.test {
    margin-top: 25px;
    margin-left: 30px;
    width: 40px;
    height: 40px;
    background-color: pink;
}
</style>

<body>
    <div class="parent">
        <div class="test"></div>
    </div>
</body>
</html>